package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.toolkit.Wrappers;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import lombok.RequiredArgsConstructor;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import java.util.*;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.BLOG_LIKED_KEY;
import static com.hmdp.utils.RedisConstants.FEED_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
@RequiredArgsConstructor
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    private final IUserService userService;

    private final StringRedisTemplate stringRedisTemplate;

    private final IFollowService followService;
    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog ->{
            this.queryBlogUser(blog);
            this.isLike(blog);
        });
        return Result.ok(records);
    }

    @Override
    public Result likeBlog(Long id) {
        if (id == null || id < 1){
            return Result.fail("博客不存在");
        }
        // 1.获取登录用户
        Long userId = UserHolder.getUser().getId();
        if (userId == null || userId < 1){
            return Result.fail("用户不存在");
        }
        // 2.判断当前登录用户是否已经点赞
        String key = BLOG_LIKED_KEY + id;
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        //3.如果未点赞，可以点赞
        if (score == null) {
            //3.1 数据库点赞数+1
            boolean success = update(Wrappers.<Blog>lambdaUpdate().eq(Blog::getId, id).setSql("liked = liked + 1"));
            if (success){
                // 3.2.保存用户到Redis的set集合  zadd key value score
                stringRedisTemplate.opsForZSet().add(key, userId.toString(), System.currentTimeMillis());
            }
        }else {
            //4.如果已点赞，取消点赞
            //4.1 数据库点赞数-1
            boolean success = update(Wrappers.<Blog>lambdaUpdate().eq(Blog::getId, id).setSql("liked = liked - 1"));
            //4.2 把用户从Redis的set集合移除
            if (success){
                // 4.2.把用户从Redis的set集合移除
                stringRedisTemplate.opsForZSet().remove(key, userId.toString());
            }
        }
        return Result.ok();
    }

    @Override
    public Result queryBlogLikes(Long id) {
        String key = BLOG_LIKED_KEY + id;
        // 1.查询top5的点赞用户 zrange key 0 4
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if (top5 == null || top5.isEmpty()){
            return Result.ok(Collections.emptyList());
        }
        // 2.解析出其中的用户id
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String idStr = StrUtil.join(",", ids);
        // 3.根据用户id查询用户 WHERE id IN ( 5 , 1 ) ORDER BY FIELD(id, 5, 1)
        List<User> list = userService.list(Wrappers.<User>lambdaQuery().in(User::getId, ids).apply("ORDER BY FIELD(id, {0})", idStr));
        List<UserDTO> userDTOS = list.stream().map(this::convertToDTO).collect(Collectors.toList());
//        List<UserDTO> userDTOS = userService.query()
//                .in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list()
//                .stream()
//                .map(this::convertToDTO)
//                .collect(Collectors.toList());
        // 4.返回
        return Result.ok(userDTOS);
    }
    @Override
    public Result saveBlog(Blog blog) {
        if (blog == null){
            return Result.fail("参数有误");
        }
        // 1.获取登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        // 2 保存探店博文
        boolean save = save(blog);
        if (!save){
            return Result.fail("新增笔记失败");
        }
        // 3.查询笔记作者的所有粉丝 select * from tb_follow where follow_user_id = ?
        List<Follow> followList = followService.list(Wrappers.<Follow>lambdaQuery().eq(Follow::getFollowUserId, user.getId()));
        // 4.推送笔记id给所有粉丝
        for (Follow follow : followList) {
            // 4.1.获取粉丝id
            Long userId = follow.getUserId();
            // 4.2.推送
            String key = FEED_KEY + userId;
            stringRedisTemplate.opsForZSet().add(key, blog.getId().toString(), System.currentTimeMillis());
        }
        // 5.返回id
        return Result.ok(blog.getId());
    }

    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        if (max == null || max < 1 || offset == null || offset < 0){
            return Result.fail("参数有误");
        }
        // 1.获取当前用户
        UserDTO user = UserHolder.getUser();
        // 2.查询收件箱 ZREVRANGEBYSCORE key Max Min LIMIT offset count
        String key = FEED_KEY + user.getId();
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        // 3.非空判断
        if (typedTuples == null || typedTuples.isEmpty()){
            return Result.ok();
        }
        // 4.解析数据：blogId、minTime（时间戳）、offset
        List<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime = 0;
        int os = 1;
        for (ZSetOperations.TypedTuple<String> typedTuple : typedTuples) {
            // 4.1.获取id
            ids.add(Long.valueOf(Objects.requireNonNull(typedTuple.getValue())));
            // 4.2.获取分数(时间戳）
            long time = Objects.requireNonNull(typedTuple.getScore()).longValue();
            if(time == minTime){
                os++;
            }else{
                minTime = time;
                os = 1;
            }
        }
        os = minTime == max ? os : os + offset;
        // 5.根据id查询blog
        String idStr = ids.stream()
                .map(String::valueOf)
                .collect(Collectors.joining(","));
        List<Blog> blogs = list(Wrappers.<Blog>lambdaQuery().in(Blog::getId, ids).apply("ORDER BY FIELD(id, {0})", idStr));
//        LambdaQueryWrapper<Blog> blogs = Wrappers.lambdaQuery(Blog.class)
//                .in(Blog::getId, ids)
//                .apply("1=1 ORDER BY FIELD(id, {0})", idStr);
        // 5.1.查询blog有关的用户
        for (Blog blog : blogs) {
            // 5.1.查询blog有关的用户
            queryBlogUser(blog);
            // 5.2.查询blog是否被点赞
            isLike(blog);
        }

        // 6.封装并返回
        ScrollResult r = new ScrollResult();
        r.setList(blogs);
        r.setOffset(os);
        r.setMinTime(minTime);
        return Result.ok(r);
    }

    @Override
    public Result queryBlogById(Long id) {
        if (id == null || id < 1){
            return Result.fail("博客不存在");
        }
        Blog blog = getById(id);
        if (blog == null) {
            return Result.fail("博客不存在");
        }
        queryBlogUser(blog);
        isLike(blog);
        return Result.ok(blog);
    }
    // 手动映射
    private UserDTO convertToDTO(User user) {
        UserDTO dto = new UserDTO();
        dto.setId(user.getId());
        dto.setNickName(user.getNickName());
        dto.setIcon(user.getIcon());
        return dto;
    }


    private void queryBlogUser(Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }
    private void isLike(Blog blog) {
        // 1.获取登录用户
        UserDTO user = UserHolder.getUser();
        if (user == null){
            return;
        }
        // 2.判断当前登录用户是否已经点赞
        String key = BLOG_LIKED_KEY + blog.getId();
        //3.判断当前登录用户是否已经点赞
        Double score = stringRedisTemplate.opsForZSet().score(key, user.getId().toString());
        blog.setIsLike(score != null);
    }

}
